This is worth thinking about in the future, thanks. I think right now, it's good to take advantage of MIRI's matched giving opportunities when they arise, and I'd expect either organization to announce if they were under a particular crunch or aiming to hit a particular target.
.impact is a volunteer task force of effective altruists who take upon projects not linked to any one organization. .impact deals in particular with implementing open-source software resources that are useful to effective altruists. Well, that's what it's trying to specialize in; the decentralized coordination of remote volunteers is very difficult.
Anyway, on the effective altruism forum, I was involved with a discussion about building an interactive visual map that updates on what the status of projects, and funding, for effective altruist organizations. ...
Many people have an incorrect view of the Future of Humanity Institute's funding situation, so this is a brief note to correct that; think of it as a spiritual successor to this post. As John Maxwell puts it, FHI is "one of the three organizations co-sponsoring LW [and] a group within the University of Oxford's philosophy department that tackles important, large-scale problems for humanity like how to go about reducing existential risk." (If you're not familiar with our work, this article is a nice, readable introduction, and our director, Nick Bostrom, wrote Superintelligence.) Though we are a research institute in an ancient and venerable institution, this does not guarantee funding or long-term stability.